Social scientists can advance this policy agenda by addressing several specific issues. First, it is important to identify individuals most at risk, as well as explanations for heightened risk. Individuals who are socially isolated may be at the greatest health risk. Several studies suggest that the relationship between social ties and health is nonlinear so that individuals with no social ties or very few social ties exhibit the most pronounced risk of poor health (Brummett et al. 2001; Cohen et al. 1997; Seeman et al. 2002). Despite the considerable evidence linking social isolation to poor health outcomes, the causal mechanisms are poorly understood. We need to investigate the possibility that differences between socially isolated and socially integrated adults—in health behaviors, emotional and instrumental support networks, physiological responses to anxiety, or other mechanisms—explain the linkage. Sociologists should direct attention to the social distribution of isolation and the possibility that the consequences of social isolation vary across social groups.
